Program: GN-2019B-Q-311

Type Ia supernovae (SN Ia) have enormous importance to cosmology and astrophysics, but their progenitors and explosion mechanisms are not known in detail. Recently, observations and theoretical models have suggested that not all thermonuclear white-dwarf supernova explosions are normal SN Ia. In particular, type Iax supernovae (SN Iax, peculiar cousins to SN Ia), are also thought to be exploding white dwarfs. Amazingly, it may be that we have a better idea about how SN Iax explode, compared to SN Ia. Here we propose to obtain Gemini spectroscopy of nearby SN Iax to test the leading SN Iax model: whether they arise from single-degenerate binary systems with a helium star donor, and whether the explosions are deflagrations that fail to completely disrupt the white dwarf, leaving behind a bound remnant. By contrasting the results from our proposed SN Iax observations with similar data from SN Ia, we may be able to constrain progenitor and explosion models for normal SN Ia as well, and thus gain a better understanding of the diverse pathways for white dwarf supernova explosions.